The general rule of antibody production is IgM antibody first, and then IgG antibody. After reaching the peak, the IgM antibody titer begins to gradually decline to a lower level, which is generally not easy to detect. IgG antibody is basically stable at a higher titer and lasts for a long time. Therefore, the positive rate of serum IgG is much higher than that of IgM. Statistics on the positive rate of torch IgG antibody in general population in China: Toxoplasma gondii is about 1 ~ 10%, rubella virus is more than 90-95%; Herpes simplex virus type 1 and cytomegalovirus account for more than 90%. Herpes simplex virus type 2 belongs to sexually transmitted diseases. The positive rate is related to the people to be tested, about 2-15%.